There are two design trends in a multiple-input and multiple-output (MIMO) technology: implementing multi-band working of an antenna and reducing couplings between multiple antennas. In a MIMO technology, a groove is etched on an antenna radiation branch to reduce couplings between antennas. Such an antenna has a simple structure and is relatively easy to implement; however, generally, impedance bandwidth is relatively narrow, and antenna radiation efficiency is relatively low. In another MIMO technology, feeds in multiple forms are introduced to one antenna, so that different patterns or polarization modes are implemented to reduce couplings between antennas. However, this structure features a relatively large size, and is suitable only for a relatively large terminal in a mobile device.